1. Field of the Invention
The present invention relates to a thrust nut that includes a plurality of nut segments that slide in an axial direction and are screwed together with a screw portion of a bolt by being rotated in a fastening direction, after the bolt is inserted to a predetermined position.
2. Description of the Related Art
This type of thrust nut of the past is configured by: a nut main body of which an outer wall is formed into a polygonal shape and that has a slanted hole in an inner wall that successively becomes smaller in diameter; a stopper piece that has a bolt insertion hole and is formed in an end portion on a large-diameter side of the nut main body; three guide pieces that are formed in an axial-center direction on an inner wall surface of the nut main body; three nut segments that are attached between the guide pieces such as to be slidable in the axial-center direction and on an inner wall surface of which threads are formed that are screwed together with the bolt; a flange-shaped attachment piece that is fixed to an end portion on the small-diameter side of the nut main body, prevents detachment of the three nut segments, and projects further outward than an outer circumferential portion of the nut main body; and a bias spring that is housed within the nut main body such as to urge the three nut segments towards the small-diameter side of the nut main body at all times.
The thrust nut, configured as described above, is configured such that the three nut segments are screwed together with a screw portion of a bolt by being inserted into the bolt and rotated in a fastening direction. However, there is a problem in that a clearance amounting to a single thread is present or not present at all times.
[Patent Literature 1] Patent Publication No. 4531585
[Patent Literature 2] Patent Publication No. 4201210